What they said. If you can't see the good in people and things then it's not them, it's you.
That's not saying there's bad out there - there is. But if you dwell on the bad or refuse to see the good in things then you're in for a long, miserable life. Or a short one. I think going to London and experiencing new things will be good for you. Nothing changes your perspective more than moving to a new area for a while. Even if it turns out the new place is worse than the place you're in it will be good for appreciating where you are now.